External measurements of implanted pacemaker characteristics. A clinical appraisal.

Edhag, O; Hofvendahl, S; Karlöf, I.; Mogensen, L.

doi:10.1136/hrt.33.2.185

Cited by 9 publications

(6 citation statements)

References 5 publications

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“…They can be accurately and rapidly performed by a trained technician and the results are available at once. Pacemaker clinics organized along these lines are now in existence in many centres (Grendahl, 1969;Edhag, Hofvendahl, Karlof, and Morgensen, 1970;Furman, Escher, Parker, and Solomon, 1969;Irnich and Effert, 1970) and experience supports our conclusions that patient supervision in this way provides additional safety against pacemaker failure and is an aid to rapid correction of pacemaker faults should they develop (Davies and Siddons, 1969;Parsonnet, Myers, Gilbert, and Zucker, 1970). The information obtainable is still limited but the methods are applicable to all pacemakers.…”

Section: Resultsmentioning

confidence: 50%

Clinical testing of implanted pacemakers

Sowton¹,

Gray²

1971

Thorax

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The function of implanted pacemakers was assessed at a special pacemaker clinic at intervals of three to six months. Measurements of the basic discharge rate of the pacemaker were made and the waveform was recovered from skin electrodes and displayed on an oscilloscope screen. The impulse was photographed from the screen and subsequent waveform analysis was carried out. Reproducible results were obtained for measurements of peak amplitude and impulse duration provided unipolar electrodes were in use and the patients were studied in the same position.The range of variation of the measurements during the lifetime of different models of normally functioning pacemakers is given. Test measurements taken before failing pacemakers were removed have been correlated with the subsequently established cause of failure and the waveform analysis test has been shown to be clinically reliable. The value of the test depended largely upon the type of pacemaker but it correlated well with rate changes in pacemakers designed to slow as battery exhaustion developed.The clinical value of waveform analysis tests is in the diagnosis of exit block, electrode failure, and premature battery exhaustion and in determining the optimum time for pacemaker replacements. The indications for replacement of pacemakers at the National Heart Hospital are given. Initial experience with an automatic analyser with three types of pacemaker shows that rapid measurements of the waveform parameters can be achieved with accuracy.

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Section: Resultsmentioning

confidence: 50%

Clinical testing of implanted pacemakers

Sowton¹,

Gray²

1971

Thorax

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“…Analysis of the pacemaker impulse with the aid of an oscilloscope is one method which has been used to reveal early bsttery exhaustion or electronic defects. Breathing-correlated variations in the amplitude may occur (Edhag et al 1971) and is one cause which makes the method somewhat uncertain. Also differences in skin resistance may cause variations in amplitude.…”

Section: Discussionmentioning

confidence: 99%

“…The indication for replacement on the basis of what was revealed by the oscilloscope test has been either a reduction in the peak amplitude of more than 30 "/o of the initial value or an increase in the initial impulse width of more than 0.2 msec. (Edhag et al 1971). The functioning of QRSsynchronous pulse generators were converted to a specified fixedralte, called the basic rate, by placing a magnet on the skin over them if the patient was not already stimulated at this rate.…”

Section: The Oscilloscope Testmentioning

confidence: 99%

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The value of an oscilloscope in routine checking of pacemakers

Edhag¹,

Fagrell²,

Sjögren³

1976

Journal of Internal Medicine

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An evaluation has been made of the usefulness of the oscilloscope at routine check-ups of cardiac pacemakers. Measurements of 100 consecutive implanted pacemakers, obtained after their removal have been compared with changes in rate and changes in impulse duration and amplitude obtained at previous routine controls. Other changes in pacemaker characteristics have also been evaluated.Eight faulty pacemakers were found. Six had a decreased voltage, none however, less than 3.5 volts. Five

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“…It is evident from several reports that sudden pacing failures cannot be completely eliminated by any follow-up system (Sowton, i967, I968;Edhag, I969;Parsonnet et al, 1970;Edhag et al,…”

Section: Discussionmentioning

confidence: 99%

Efficiency of a pacemaker clinic to prevent sudden pacing failures.

Frick¹

1973

Heart

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Two hundredpatients with implantedpacemakers werefollowed in a pacemaker clinic over a period of 3years. The follow-up times ranged from I to 36 months, with a mean of 22 months. The material represents 366 patient-years ofpacing and 361 pacemakers. One hundred and twenty replacements were done. Most of these were elective (93%) and based on gradual deterioration of the pacing detected by photoanalysis of the generator impulse. Of the single variables the duration of the impulse and the discharge rate were most revealing; recording changes in these two variables led to 96 per cent failure detection. There were 28 deaths within the follow-up time: 3 of them were related to pacing failure and 5 were possibly so. When these sudden fatal events were added to the sudden nonfatal failures not detected by the routine control system a I6 per cent failure rate of detection emerged. The total annual mortality was 7.7 per cent. The mortality caused by pacing failures was 2 2 per cent per annum.After the primary descriptions of the significance of impulse analysis in detecting pacemaker failures (Davies and Sowton, i964;-Nickel, I964; Knuckey, McDonald, and Sloman, I965) organized special pacemaker clinics have gained wide acceptance. The primary goal is to prevent sudden pacing failures, with the associated mortality and morbidity, and to get the maximal life span out of each implanted unit (Siddons and Sowton, I967; Thalen et al., I969). While it is evident that the number of emergency replacements is greatly reduced, they still occur (e.g., Parsonnet et al., I970; Furman, Escher, and Parker, I97Ia), and a number of patients succumb outside hospital from pacing failure without detailed data on the mode of death.A pacemaker clinic has been in operation in Helsinki University Central Hospital since I968. This report is based on the analysis of its efficiency in preventing pacing failures during a period of three years. Patients and pacemakersDuring the time of analysis 207 patients were followed in the clinic. Seven of them were lost to follow-up (3 transferred to other hospitals, 2 moved abroad, 2 not traced), leaving 200 patients, 103 women and 97 men, for analysis. The age ranged from 28 to 88, with a mean of 6i years. The follow-up ranged from I to 36 months, Received 2 JUIy I973. with a mean of 22 months. All together this represents 366 patient-years. The pacemaker material consisted of 36I units, 207 of which were Elema-Sch6nander (Types 139, I52, 153), io6 Vitatron (Types 150, 400 R), and 48Medtronic (Types 5841, 5842 d, 5843 d, 5860, 5862, 5868, 5870). Only two units functioning normally were replaced solely because they approached the maximal life span reported by the manufacturer. These have been excluded from the analysis. All the other units have been followed to the point when clear-cut indications for replacement became evident or sudden failure occurred.Endocardial pacing was accomplished in 20I instances while i6o units were connected to epicardial electrodes inserted either earlier or simultaneously throug...

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External measurements of implanted pacemaker characteristics. A clinical appraisal.

Cited by 9 publications

References 5 publications

Clinical testing of implanted pacemakers

Clinical testing of implanted pacemakers

The value of an oscilloscope in routine checking of pacemakers

Efficiency of a pacemaker clinic to prevent sudden pacing failures.

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